Standard C Date/Time Library: Programming the World's Calendars and Clocks

Lance Latham's Standard C Date/Time Library aims to solve the problem with time and calendars on computers. This book publishes the author's C library with functions (included on CD-ROM) for many of the world's calendars, interspersed with some truly fascinating historical material that makes sense of humankind's myriad attempts to get a handle on time.

The Standard C Date/Time Library begins with a description of the Y2K problem. The author then proceeds to show that definitions of years, months, and days are subject to different standards, many of which are the result of "applied astronomy." He develops his comprehensive solution using the Julian calendar and represents hours and minutes as fractions of days. His Standard C Date/Time Library (STDTL) offers extremely comprehensive functionality, allowing you to calculate differences between days and days of the week, as well as calculations for holidays.

The author intersperses source code listings with wide-ranging descriptions of calendars and their inconsistencies. For the treatment of the Western calendar and ISO 8601 standard time functions, this code library is worth it. However, the author goes much further and offers code for and descriptions of all the major calendars of the world, including non-Western calendars and ancient calendar systems. --Richard Dragan